Sweeteners are well known as ingredients used most commonly in the food, beverage, or confectionary industries. The sweetener can either be incorporated into a final food product during production or for stand-alone use, when appropriately diluted, as a tabletop sweetener or an at-home replacement for sugars in baking. Sweeteners include natural sweeteners such as sucrose, high fructose corn syrup, molasses, maple syrup, and honey and artificial sweeteners such as aspartame, saccharine and sucralose. Stevia extract is a natural sweetener that can be isolated and extracted from a perennial shrub, Stevia rebaudiana. Stevia is commonly grown in South America and Asia for commercial production of stevia extract. Stevia extract, purified to various degrees, is used commercially as a high intensity sweetener in foods and in blends or alone as a tabletop sweetener.
Extracts of the Stevia plant contain rebaudiosides and other steviol glycosides that contribute to the sweet flavor, although the amount of each glycoside often varies among different production batches. Typically, stevioside and rebaudioside A are the primary compounds in commercially-produced stevia extracts. Stevioside is reported to have a more bitter and less sweet taste than rebaudioside A. The composition of stevia extract can vary from lot to lot depending on the soil and climate in which the plants are grown. Depending upon the sourced plant, the climate conditions, and the extraction process, the amount of rebaudioside A in commercial preparations is reported to vary from 20 to 97% of the total steviol glycoside content. Other steviol glycosides are present in varying amounts in stevia extracts. For example, rebaudioside B is typically present at less than 1-2%, whereas rebaudioside C can be present at levels as high as 7-15%. Rebaudioside D is typically present in levels of 2% or less, Rebaudioside M is typically present in trace levels (<0.1%), and rebaudioside F is typically present in compositions at 3.5% or less of the total steviol glycosides. The amount of the minor steviol glycosides can affect the flavor profile of a Stevia extract.
Chemical structures for several of the compounds found in Stevia extracts are shown in FIG. 1, including the diterpene steviol and various steviol glycosides. CAS numbers are shown in Table 1 below. See also, Steviol Glycosides Chemical and Technical Assessment 69th JECFA, prepared by Harriet Wallin, Food Agric. Org. (2007).
TABLE 1COMPOUNDCAS #Steviol471-80-7Rebaudioside A (RebA)58543-16-1Steviolbioside41093-60-1Stevioside57817-89-7Rebaudioside B (RebB)58543-17-2Rebaudioside C (RebC)63550-99-2Rebaudioside D (RebD)63279-13-0Rebaudioside E (RebE)63279-14-1Rebaudioside F (RebF)438045-89-7Rebaudioside M (RebM)1220616-44-3Rubusoside (Rubu)63849-39-4Dulcoside A64432-06-0